Process for the coagulation of castilloa latex



Patentecl Nov. 12, 1946 'PROCESS FOR THE COAGULATION 0F CASTILLOA LATEXv l 'iCrey Foster Forth Arlington, Va., assigner to United States of America, as represented by the Secretary of Agriculture v No Drawing.

Original application August, 31, i

1943, Serial No. 500,649. Divided and this application November 23, 1945, Serial No. 630,517

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 3 Claims.

l This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described, if patented, may be manufactured and used by or for only Within a narrow concentration range and is less satisfactory than the results which can be obtained by additional use of an acid substance. With tri-sodium phosphate and sodium carbonate,

the Government of the United States of America 5 coagulation is not brought about as easily nor is for governmental purposes without the payment the coagulum as workable as obtained by using an to me of any royalty thereon. alkaline substance and an acid substance or salts. This application is a division of copending ap- Tri-sodium phosphate and sodium carbonate are plication for patent, Serial No. 500,649, filed probably effective because they are strongly alka- August 31, 1943. 1o line salts, and are capable both of dissolving the This invention relates to the coagulation of protective proteins and of precipitating the re- Castilloa latex which in its natural state is norsulting colloidal systems. mally stable when treated With acids, and has The following examples, each employing a among its objects a process for the coagulation sample of cc. of undiluted Castilloa latex, which of such latex in a simple manner. 15 had not been previously treated by washing or Hevea rubber latex is readny coagulabie by acid otherwise, are illustrative of the process of coagsubstances and such coagulation is an essential ulation of this invention. step in most commercial methods of preparing Example I I-Ievea rubber. Similar methods cannot be used with Castilloa latex. Commercial 'development 20 A mixture 0f the Sample 0f 131119K and 1 CC- 0f of casuuoa rubber has been retarded by the dir- 10 Percent NaOH gave n0 Coagulum in the @01d ficulty and uncertainty of the primitive methods 01' 0n Warming- Addition 0f 1 CC- 0f 18 percent now in use in ooagulating its latex HC1 to the heated mixture immediately produced I have found that Castilloa latex can be coaga Coagulnln Which Was @Onerent and of good texulated by acid substances and salts used for coagtum 5111111511 results Were Obtalned by repeatmation of Hex/eau latex, provided the oasmioa ing the Process, except that the beaune Was a0- latoX s mst treated with dilute ammonia, oaus complishedafter the treatment with the hydroxide tic soda, or other alkaline substances, and in the and the 3mdoaso of aoid Substances suon are used in Sun-j- Instead of using HC1, good results were also obcient quantity to neutralize the alkaline substance tained by using 1 CC- 0f 10 peICenl I12504, 2 C0- and coagulate the rubber. Gentle heating is nec- 0f 10 Percent acefc acid 0r 1 CC- 0f 10 percent essary to produce rapid and satisfactory coagu- 1131304- COagU-latlon Was 3150 Produced by Sing lation and clumping of the rubber, but the heat- 1% CC- 0f 10 Pe1`0ent formi@ acid but the Coaguing can be at any time during or after addition 111m Was gramy. of the alkaline and acid substances or salts. Example II Although the mechanism of the treatment is A mixture of the sample of latex and 1 ca of not known, probably 1ts effect 1s to dissolve sub- 10 no1-Cont NaOH gave no ooagnlum in one cold stances other lthan rubber from the surfaces of or on Warming on adding 10 oo of 10 percent the latex partlcles. So long as these substances, NaCl a ooagulnm Was obtained which was only which are probably proteins, coat .the particles, loosely coherent, A compact, though grainy, they cause the part1cles to be pos1t1vely charged, ooagulum was obtained by substituting 2 oo of and therefore, to be uncoagulated by positive ions. 10 percent Cock for tno NaCL Removal of these substances by the alkaline sub- The sans mentioned above when used alone did stance does not of itself produce coagulation, benot produce Coagulation cause negative rubber particles remain, which, like Hevea latex particles, are stabilized by alka- Example IH line substances. Like Hevea latex particles, how- A mixture of the sample of latex and 2 cc. of ever, they are noW coagulable by acid substances 10 percent NaaPO4 gave on heating a grainy, nonand salts used for coagulation of Hevea latex. coherent coagulum. Addition of 1 cc. of 10 per- I have also found that use of certain alkaline cent HC1 and slight boiling produced clumping of substances, including alkaline salts such as trithis coagulum. A mixture of the sample of latex sodium phosphate and sodium carbonate, and and 2 cc. of 10 percent NazCOa gave on heating a even sodium hydroxide and ammonium hydroxloose coagulum. ide, can produce coagulation alone. In the use Heating the untreated latex or boiling it alone of sodium hydroxide, however, coagulation occurs did not produce coagulation. Neither was coaguof the latex to one part of the NaOH, and then l0y with an acid substance in suiiicient quantity to neutralize the NaOH and coagulate the rubberl ber.

and heating to facilitate coagulation of the rub- 2. A process for coagulating Castilloa latex comprising treating untreated Castilloa latex with dilute NaOH in the ratio of about 15 parts of the latex to one part of the NaOH and then with about 10 parts of dilute NaCl solution, and heating to facilitate coagulation of the rubber.

3. A process for coagulating Castilloa latex comprising treating untreated Castilloa latex with dilute NaOH in the ratio of about 15 parts of the latex to one part of the NaOH and then with about 2 parts of dilute CaCl: solution, and heating to facilitate coagulation of the rubber.

TIREY FOSTER FORD. 

